Data

RPMs are probably proportional to Amps in, given same battery input

From 9-V off-the shelf battery (largely dicharged). They did not have enough juice to run the rotor at any particular speed constant, but the deceleration rate was so slow that at first it appeared the speed was constant. Indeed, the speed may have been (probably was) constant at first. I did not document the speed consistency until about two hours of operation. The batteries may have been depleted enough by then to stop holding a constant speed. This, actually, is probably a preferred scenario for this particular experiment -- depleted battery that has enough juice to largely over come the friction of rotation, but not enough to maintain a constant speed.

Manually sped up or slowed down rotation speed (gradually slows at each speed, more so on higher speeds).

Manutally counted rotations.

Amp meter only reads to two digits to the right of the decimal place.

Margin of error is farily high.

18 rpm : 7.7 v 0.01 amp = .08 W

: (slower rpms measured for just 10 seconds)

30 rpm : 7.4 v 0.02 amp = .15 W

36 rpm : 7.0 v 0.03 amp = .21 W

40 rpm : 7.2 v 0.03 amp = .22 W

45 rpm : 6.7 v 0.04 amp = .27 W

48 rpm : 6.9 v 0.04 amp = .28 W

60 rpm : 6.8 v 0.05 amp = .34 W

78 rpm : 6.6 v 0.06 amp = .40 W

95 rpm : 6.1 v 0.07 amp = .42 W

114 rpm : 6.3 v 0.08 amp = .50 W

149 rpm : 6.0 v 0.09 amp = .54 W

These data are rough, no attempt was made to reproduce them.

Conclusions

I've not plotted the above data yet, but a quick look indicates that the relationship is probably linear. Double the speed = double amps.